In modern technology, electronic components that are arranged on printed circuit boards are often used. To be able to produce such printed circuit boards in large numbers, it is known to use automatic placement machines. In such automatic placement machines, electronic components are arranged on the printed circuit boards by one or more placement heads. The electronic components required for this are often made available on what are known as component belts, which are fed to the actual placing operation by the placement heads by belt conveyors, which may be part of the automatic placement machines. In such belt conveyors, the transporting of the placed-in belts often takes place by what are known as pinwheels, the pins of which can engage in perforations of the belts. To ensure reliable functioning of the automatic placement machine, in particular to ensure that the placement head of the automatic placement machine can reliably pick up the fed electronic components, great accuracy of the positioning of the fed belt is necessary. It may be necessary here to determine the absolute angular position of the pinwheel of the belt conveyor with an accuracy of ±0.035°.
It is known in the case of belt conveyors to use position-determining devices that have a magnetoresistive sensor arrangement. In such a magnetoresistive sensor arrangement, the AMR effect (anisotropic magnetoresistive effect) for example may be used here for the measurement. It is known here to adhesively attach a magnetized pole wheel, formed in particular as an injection-molded part, directly onto the pinwheel. Even this adhesive attachment of the magnetized pole wheel has to be performed here with high precision. The magnetoresistive sensor arrangement of the position-determining device allows the various magnetic poles of the magnetized pole wheel to be measured, and consequently the position of the pinwheel on which the magnetized pole wheel is adhesively attached to be determined. However, for this purpose it is also necessary that the distance between the magnetoresistive sensor arrangement and the pole wheel must be adjusted very accurately during the mounting of the sensor arrangement. This can be achieved for example by the magnetoresistive sensor arrangement being cast in a casting compound, and the necessary distance between the sensor arrangement and the magnetized pole wheel being set in an iterative process, during the mounting. This set distance must then be ensured for as long as it takes until the casting compound has cured. Altogether, the method and the arrangement of the sensor arrangement for measuring the exact position of the pinwheel according to the prior art, in particular with respect to the mounting, thus represents a very laborious procedure.